There are a variety of methods for printing and constructing organic structures on surfaces, and these methods are leading to significant advances in the understanding of the chemical consequences of miniaturization and the application of patterned surfaces in fields ranging from microbiology to electronics to catalysis. Micro-contact printing and variants of it are useful approaches for printing organic structures on surfaces because they are massively parallel and allow for the control of feature size, typically down to 200 nm. Among the scanning probe-based methods, Dip-Pen Nanolithography (DPN) has emerged as a powerful tool to do highly customized work in direct write fashion with a resolution that rivals electron beam lithography. Indeed, small organic molecules, oligonucleotides, proteins, conducting polymers and sol gels have all been patterned on inorganic substrates such as gold, silver, and silicon oxides with sub-50 nm resolution. Although advances have recently extended single-pen DPN approaches to parallel multi-pen approaches, the throughput of DPN cannot rival the available printing processes. Thus, an ideal method of forming organic nanostructures would have the high throughput of the printing processes but the resolution, alignment, registration and multi-ink capabilities of DPN.
One approach to fabricating highly miniaturized organic nanostructures is to controllably reduce the size of an existing organic structure. Previously, electrochemical methods have been used to effect the bulk desorption of adsorbates from self-assembled monolayers (SAM) coated on gold electrodes. It was proposed that the desorption process initiated from defect sites within the monolayers. It is also known that for materials in general, surface sites are typically more reactive than bulk sites.
Thus, there is a need for a method of reducing the size of an organic structure on a substrate by applying a potential in a controlled manner to selectively shrink features in a uniform manner at a controllable miniaturization rate.